Russia could deploy offensive missiles on its western and southern borders to target NATO missile defense installations in Europe should the U.S. continue to refuse to comply with Russian demands over the proposed NATO system, Russian President Dmitry Medvedev said today.

Medvedev said the U.S. and NATO have "not shown enough willingness" to address Russia's security concerns about the new U.S.-maintained and Europe-based missile defense system that he said would "eventually see the deployment of U.S. missiles and military capability in close proximity to Russia's borders and in the neighboring waters."

In response, Medvedev said in a speech to the nation he has issued four orders to his military including putting a radar early warning system on "combat alert," equipping some of the nation's missiles with "advanced missile defense penetration systems," and developing measures to knock out the missile defense guidance systems. Should such measures still "prove ineffective," the Russian leader said more drastic and strategically offensive measures could be taken.

"The Russian Federation will deploy modern offensive weapon systems in the west and south of the country, ensuring our ability to take out any part of the U.S. missile defense system in Europe," Medvedev said.

Medvedev also repeated a threat to withdraw from the new START treaty, the latest version of the nuclear disarmament agreement that President Obama said in November 2010 was "a cornerstone of our relations with Russia" and a "national security imperative."

President Obama's National Security Council said that the missile shield does not threaten Russia's security, but is meant to protect many countries against Iranian missiles, and such threats by Medvedev were baseless.

"The United States has been open and transparent with Russia on our plans for missile defense in Europe, which reflect a growing threat to our allies from Iran that we are committed to deterring," the council's spokesperson Tommy Vietor said today. "[The START treaty] implementation is going well and we see no basis for threats to withdraw from it."

Vietor said the U.S. was committed to cooperating with Russia on security issues but said "in pursuing this cooperation, we will not in any way limit or change our deployment plans in Europe."

The missile defense shield will be deployed in 2020 and would include advanced radar systems and interceptor missiles at land and sea locations in Europe. NATO had proposed the defense shield work separately but in coordination with a counterpart system in Russia, but Russian officials pushed for a joint operation. Medvedev said in March it could take until 2020 for Russia and the U.S. just to come to an agreement.

Among Russia's demands, Medvedev said, was that, beyond verbal assurances, NATO put down in writing specific legal provisions for how the missile shield would work, including "military-technical criteria that will enable Russia to judge to what extent U.S. and NATO action in the missile defense area correspond to their declarations and steps, whether our interests are being impinged on, and to what extent the strategic nuclear balance is still intact."

"This is the foundation of the present-day security," he said. Medvedev said that demand was "firmly rejected."